1. Field of Invention
This invention relates generally to air diffusion devices for use in environmentally controlled work spaces where conditioned air is introduced uniformly from diffusers located in the ceiling of the work space above a work area. Because of low inlet velocity, the air maintains a downward laminar flow to outlets at the base of the workspace, thereby air turbulence within the space. By minimizing turbulence, circulation of pollutants, such as bacteria or dust, which may have settled in the lower portion of the space, is minimized insuring that the quality of the ambient air in the work area has not been reduced by the circulation of pollutants.
2. Description of Prior Art
The use of pressure-displacement type diffusion devices to distribute conditioned air is exemplified by U.S. Pat. No. 2,304,628 where air is introduced at low velocities throughout the length of a railroad passenger car. As exemplified in U.S. Pat. No. 2,585,666, each diffusion device incorporates structure allowing easy access to an adjustable valve to control the amount of air passing through the individual device. Low velocity diffusion was also adapted for use within a "clean room" to achieve laminar air flow as exemplified by U.S. Pat. No. 3,367,259. The structure of a laminar flow air diffusion device for use within a clean room is further exemplified by U.S. Pat. No. 3,570,385, wherein a light fixture and filter are combined in a diffusion unit.
Prior module designs have failed to provide structure allowing for a simplified and quick balancing of the installation.
Balancing multiple units arranged in a ceiling was difficult and time consuming from a standpoint of access to individual valve controls and specially designed bulky measuring devices for sensing air flow velocity.
Heretofore, the process of balancing air output was most difficult because air velocity was measured at the outlet of each module, which in most all cases was a perforated plate. Because of the low velocity of the air at this point, a standard anemometer could not be used directly. Instead, balancing was attempted by use of funnel devices having a pre-selected one-square foot inlet area and tapering to a narrowed end where there was sufficient air velocity to activate an anemometer and give a reading. Numerous adjustments had to be made to the module to achieve an equal velocity of air output for each square foot of perforations.